Driving on steep road grades?

[outdoors5]

We are excited about going out to the national parks this summer such as Glacier National Park, Yellowstone, Zion, Bryce, N. Grand Canyon, Arches, and into Colorodo with stops there such as Rocky Mtn. National Park-Estees Park. I have never traveled in such regions with many steep roads.  

My question is about towing the PU on steep roads, which seem to be difficult to avoid.  Is there a general rule of thumb for what percent road grades and/or length of a steep road that should be avoided going up hill or down hill?  Or is taking it slow and carefull safe enough?  

Note:  My tow vehicle is a '03 GMC Yukon XL 1500, V8 5.3L engine, 7100 pound tow rating.  The PU is a 2000 Niagara Fleetwood/Colemen weighing just under 3000 pounds, plus the extra weight due to camping gear.

[wavery]

We are excited about going out to the national parks this summer such as Glacier National Park, Yellowstone, Zion, Bryce, N. Grand Canyon, Arches, and into Colorodo with stops there such as Rocky Mtn. National Park-Estees Park. I have never traveled in such regions with many steep roads.  

My question is about towing the PU on steep roads, which seem to be difficult to avoid.  Is there a general rule of thumb for what percent road grades and/or length of a steep road that should be avoided going up hill or down hill?  Or is taking it slow and carefull safe enough?  

Note:  My tow vehicle is a '03 GMC Yukon XL 1500, V8 5.3L engine, 7100 pound tow rating.  The PU is a 2000 Niagara Fleetwood/Colemen weighing just under 3000 pounds, plus the extra weight due to camping gear.

You should have very little difficulty with your set-up.

[Dee4j]

on steep down grades, save your brakes and down shift to 2nd you can go about 55 mph to 60 in 2nd..when going uphill take your auto transmission out of over drive

['tiredTeacher]

when going uphill take your auto transmission out of over drive

I second and add it's a good idea to take it out of overdrive going downhill, too, to increase engine breaking. I disengage the OD in hilly country, as per Toyota's instruction, to save transmission wear.

[maddawg04]

you might want to consider installing an electric brake controller on your tv (if u haven't done so already).*

[tlhdoc]

I agree with the others.  I will also add that if you have climbed a very steep mountain take a break at the top and give the TV time to cool off before going down the other side.

[flyfisherman]

I have a regular cab, short box, '02 GMC Sierra with a 4.8 V-8 and tow a small Starcraft with a GVWR of 2090 lbs., and that's pretty close to the actual weight when we're tooling down the road. Plus I carry a lot jun... eh, stuff, in the bed of the truck. Anyway, it's an easy pull, but still ... a ton is a ton (plus the cargo!) ~

Try to make the cruise speed 65 mph as that's what the camper tire manufacturer's say is top speed for the tires; plus I get good gas mileage (for a truck!). Level country side driving I tow in regular O/D. When I get into the rolling hills I use the "Tow'Haul" mode of the automatic transmission, but leaving the tranny selection in O/D. When I get into the mountains I drop into regular 3rd and just leave it there, whether ascending or decending the mountain grades.




Fly

[austinado16]

... I will also add that if you have climbed a very steep mountain take a break at the top and give the TV time to cool off before going down the other side.

tlhdoc....With all due respect, this is not what to do.  It takes airflow through the radiator, engine oil cooler and transmission oil cooler to cool down these vital fluids.  It's the back side of the hill that provides all this for free, instantly.  DO NOT stop at the top of a long grade.

outdoor5......You've got an outstanding TV and it'll do just fine.  A couple things to look at prior to the trip (someone's already touched on the trailer brake setup)
1) Condition of your brakes as far as, how thick are the front pads and rear shoes.  Are the rear shoes adjusting properly on their own.  Are the front brake rotors still pretty smooth and nice.  If you need brake work, be sure to select uprated brake pads for the front, don't let a shop install some cheap-o pads.

2) Condition of the radiator fan clutch.  It should really roar for the first 1/2 mi or so after initial cold start, and then become completely quiet.  If yours still does this, then it's probably fine.  It should, of course, also roar when it gets very hot out.

3) You might consider upgrading your transmission oil cooler.  Pop the hood and take a look at how large it is, and then compare that to what's available in the aftermarket from Hayden and others.  Heat is the instant death of automatics so the biggest thickest cooler you can fit is well worth it.

4) Consider putting in synthetic transmission fluid....it will take the heat of towing much better!  

I'm towing with an older version of your TV.  Don't have brakes on the PU, or synthetic in the trans, but I've done everything else.  We do alot of hilly driving and towing, and I've never had a problem up or down.  

But take the advice on shifting into lower gears and save your brakes!  Keep some extra distance in front of you and don't be the "guy" who rides the brakes all the way down the hill.....once the brakes get hot, you start losing braking ability and things can get hairy fast descending a steep grade with a 2,000lb trailer pushing you!  3rd gear or 2nd gear and light brief taps on the brakes, on the straight stretches is best.

[tlhdoc]

tlhdoc....With all due respect, this is not what to do. It takes airflow through the radiator, engine oil cooler and transmission oil cooler to cool down these vital fluids. It's the back side of the hill that provides all this for free, instantly. DO NOT stop at the top of a long grade.

I didn't say to shut your vehicle off, just to stop and let things cool down.  Using your transmission as a brake is not going to allow the transmission fluid to cool down.
 

light brief taps on the brakes, on the straight stretches is best.

If you only do light taps on the brakes you may not engage all 4 of your brakes.  When breaking you want to slow down at least 10 mph before letting up on your breaks, so that the brakes to all of the wheels are applied.  That way you are using all 4 brakes and not just 2 of them.

[austinado16]

I didn't say to shut your vehicle off, just to stop and let things cool down.  Using your transmission as a brake is not going to allow the transmission fluid to cool down.
 
 
If you only do light taps on the brakes you may not engage all 4 of your brakes.  When breaking you want to slow down at least 10 mph before letting up on your breaks, so that the brakes to all of the wheels are applied.  That way you are using all 4 brakes and not just 2 of them.

I'm sorry, but this is absolutely not how automotive brake systems work.  Nor is it how transmissions work.

All automotive brake systems apply all of the brakes on a vehicle. Period.  Using the transmission to control speed does not load the transmission and heat it up.  Light braking is correct for hill descents and it's all that's typically needed if you control your speed starting at the top and maintain a good space between you and cars ahead so you're not at the end of the traffic slinky.

Pulling over at the top of a grade and idling is absolutely the wrong thing to do.  Idling moves very little air through the radiator, transmission cooler and oil cooler.   The engine idles at 800rpm, so if the fan clutch is engaged, you'd have a radiator fan turning 800ish rpm depending on pulley ratio.  Compare this to driving down the back side of the hill at normal speeds and having the ram effect of 50+mph wind forcing through the radiator and coolers, and the fan turning at an engine speed of 2,000-2,900rpm depending on the gear your in.

I'm not trying to turn this into a fight, but all the information you've posted is incorrect.

[pricerj]

We are excited about going out to the national parks this summer such as Glacier National Park, Yellowstone, Zion, Bryce, N. Grand Canyon, Arches, and into Colorodo with stops there such as Rocky Mtn. National Park-Estees Park. I have never traveled in such regions with many steep roads.  

My question is about towing the PU on steep roads, which seem to be difficult to avoid.  Is there a general rule of thumb for what percent road grades and/or length of a steep road that should be avoided going up hill or down hill?  Or is taking it slow and carefull safe enough?  

Note:  My tow vehicle is a '03 GMC Yukon XL 1500, V8 5.3L engine, 7100 pound tow rating.  The PU is a 2000 Niagara Fleetwood/Colemen weighing just under 3000 pounds, plus the extra weight due to camping gear.

With your setup you should be just fine. I'm not even sure you need the "slow" in your "slow & careful" question.  Last year we did a SoCal to Rocky Mountain National Park trip (Bryce, Zion & Arches were part of it as well). With a 6-Cylander Honda Pilot towing a Fleetwood Sea Pine the only towin' slow spot we hit was 70 East going up the Vail pass. I'm sure your rig will do much better than ours, but I'd still love to hear how Vail Pass affects you.

[outdoors5]

Thanks for all the information.  
How do I find the transmission cooler and oil cooler in the tv and how do I know if I have and adequate one.

[austinado16]

Thanks for all the information.  
How do I find the transmission cooler and oil cooler in the tv and how do I know if I have and adequate one.

I wouldn't sweat any of this too much, you've got a fantastic TV that's a tried and true hauler.....that's all it's been built to do since the 50's.  It'll tow your PU as if it weren't even there.

Depending on how your Yukon is set up, it may be using a transmission oil heat exchanger built into the radiator and that's it, or it could have an external transmission oil cooler plumbed "in line" after the heat exchanger.

Pop the hood and look at the back side of the radiator.  You will see steel lines going to one of the radiator tanks. Those are from the transmission and they go into a metal coil inside the radiator tank.  This does 2 things.  On cold startup, the coolant reaches tempurature faster than the transmission oil.  So the hot coolant is used to help warm the trans oil faster so you get proper protection and lubrication as fast a possible.  During hot driving, the coolant stays in the 195-210F range and therefore helps keep the transmission oil down to this range as well.   But for real serious towing, it's nice to have a big external cooler mounted out in front of the radiator, just behind the grill.  Take a look through the grill with a flashlight and see if there's a small radiator looking component that is plumbed into the metal lines running from the trans to the radiator tank.

Below is a photo with my grill removed.  The cooler on the left is the transmission cooler that I've added, the cooler on the right is the factory installed engine oil cooler.

[CajunCamper]

Outdoors5,

If I were you I would choose the route to the campgrounds you'll be staying in carefully. There's usually a scenic route (the scenic route usually means more difficult driving conditions while towing) and a not so scenic route going in to these places. When I'm traveling without my pup in tow, I usually select the scenic route, because the steep grades are not an issue, but with my pup in tow, I usually look for an easier route. Once I'm set up in my campsite, I can then use my vehicle to explore any roads I like. Remember, the advice I give comes from a guy that lives in one of the flatest states in the country, so my experience in mountain country is limited.

Happy Camping.

CajunCamper

[wavery]

Below is a photo with my grill removed.  The cooler on the left is the transmission cooler that I've added, the cooler on the right is the factory installed engine oil cooler.

If you have A/C, I would be careful about adding a trans cooler that completely covers the radiator like that. It could seriously impede the air flow that must pass through 3 layers of finned coolers.

When climbing hills with the A/C on, the air that finally reaches your radiator, is super heated and there isn't a lot of area for your radiator to receive any (relatively) cool air.

If you install a cooler that large you may want to consider adding a "Pushing" fan in front of the cooler. That way you will have additional air when it is need the most.....while struggling up a grade at reduced speed and reduced natural air flow.